The phrase "end-all" means the ultimate goal or final solution to a problem. Synonyms for this word could include "be-all and end-all", "culmination", "ultimate", "conclusion", "termination", "destination", "finale", "climax", "resolution", "omega", "perfection". It is important to note that some of these synonyms may have slightly different meanings. For example, "perfection" may imply more of an ideal state rather than a singular solution. But overall, these words can be used interchangeably with "end-all" to convey the idea of a definitive end point or ultimate solution.